Data storage devices (DSDs), such as disk drives and solid state drives are employed in numerous areas such as computer systems (e.g., desktops, laptops, portables, etc.) and consumer devices (e.g., music players, cell phones, cameras, etc.). User data is typically stored in a non-volatile memory, such as a magnetic disk or a non-volatile semiconductor memory (e.g., Flash memory). When a power failure occurs, it may be desirable to complete pending write commands prior to safely shutting down the DSD so that user data is not lost. This is of particular concern in DSDs that cache write data in a volatile semiconductor memory prior to writing the data to the non-volatile memory. A conventional DSD may charge a capacitor to a high voltage using the power supplied by the host, and then use the capacitor voltage to power circuitry in the DSD to flush a write cache during a power failure. Using a high voltage capacitor to generate the backup power is more cost effective compared to using a lower voltage capacitor or bank of capacitors.